250-500cc Best online shop for 300 performance parts?

Is there any particular online shop I can order 300 parts at good prices?

I want to get:
PWK Keihin 38 carb
Is this the best place: http://www.jdjetting.com/xcart/product.php?productid=60&cat=3&page=1
(Bugger it, just ordered the carb couldnt help myself LOL


Race head ?

Is it worth replacing the factory tailpipe with an aftermarket one? The Husky shop replaced the front pipe but left the factory rear on :S


Cheers
S

motosportz.com

I dont think they have the race head. I heard that there was suppose to be a Husky Power PArts catalogue but I cannot find it anywhere.